Nosocomial infections or Health Care Associated Infections (HCAIs) are a major financial and safety concern in hospitals and Health Care Service Units (HCSUs) worldwide. HCAIs are defined as infections that result from treatment or care of a patient within a hospital or health care service unit but are secondary to the patient's original presenting condition. The prevalence of these HCAIs has increased dramatically in the last century as a result of a number of significant factors, most notably the emergence of antibiotic or anti-microbial resistant strains of a large range of common microorganisms. Additional factors related to the increased prevalence include consolidation of hospitals/health care service units nationally (resulting in larger numbers of patients housed together, often in an immunocompromised state), increased use of outpatient treatment (consequently people in hospitals are sicker on average as a direct result), the movement of medical staff and personnel from patient to patient acting as vectors for disease transmission, lack of rigid sanitation protocols and/or enforcement, and the over-prescription of antibiotics or anti-microbial drugs.
The prevalence of these nosocomial infections is extremely relevant clinically. In the United States (US), it is estimated that the rate of HCAI prevalence is as high as 10% (or two million patients infected) per annum (p.a.). The proportion of these two million infected patients that result in patient morbidity is about 5% or 100,000 deaths p.a. Encouragingly it is estimated that at least one third of all nosocomial infections are preventable with the effective application of sufficient disinfection precautions. In Europe, the morbidity rate is very similar with prevalence rates of approximately 7% in France, 7% in Italy, 7.6% in England, 8.2% in Wales and 5.5% in Northern Ireland. The Republic of Ireland has the lowest prevalence rate of 4.9%. Annual estimated costs for HCAIs run as high as $11 billion in the US (approx 0.1% of US GDP) and £1 billion in the UK (approx 0.05% of UK GDP) with a potential avoidable cost of at least £150 million p.a. in the UK alone.
There are many infectious diseases associated with hospital and HCSUs. Several routes of transmission are commonly available in all these settings, specifically (i) contact, (ii) droplet, (iii) airborne and (iv) common vehicle transmission. High touch surfaces such as door handles, door knobs etc. are extremely effective reservoirs for contact-transmitted infections and can support a large number of different strains of infectious microorganisms. These contact-transmitted infections include Acinetobacter (pneumonia), Burkholderia cepacia (respiratory infections), Clostridium Difficile (intestinal infections, diarrhoea), Colstridium Sordelli (nausea, vomiting), Viral Haemorrhagic Fever, gastrointestinal infections, Hepatitis-A (liver disease), Methicillin-resistant Staphylococcus Aureus (MRSA), Parvovirus, and Severe Acute Respiratory Syndrome (SARS). Although immunocompromised patients are most at risk, HCAI microorganisms are widespread and carried on a large proportion of the population's skin with significant morbidity in non-immunosuppressed patients. Worryingly, prevalence rates are largely underestimated as currently data is only collected in the more serious cases of HCAI. MRSA is the best known of all these contact-transmitted HCAIs, with 10% of all HCAIs being attributed to MRSA alone and approximately 33% of the population carrying MRSA. Previous scientific studies have shown worrying evidence of high-touch surface contamination within hospitals and HCSUs. Staphylococcus Aureus identified on approximately 30% of all room door handles, suggesting extensive contamination within these environments. Consequently, MRSA is almost universally used as the benchmark for all qualitative and quantitative measures of HCAI prevalence and curative efficacy.
Successful preventative and curative measures in the past have targeted several routes of transmission to counteract the rapid spread of HCAIs. Traditionally, these measures have focussed on the most obvious route of infection, namely through direct contact transmission (e.g. body surface to body surface, hand contact between source and prospective host). The promotion of hand washing is frequently seen as the single most important measure currently employed to reduce risk of infection, with the adoption of alcohol-based hand gels being recommended as the primary means of hand hygiene in Irish, Centre for Disease Control (CDC) and World Health Organisation (WHO) published guidelines. Measurement of the consumption of alcohol-based hand gels, expressed as volume per bed days, has been shown to correlate with overall hand hygiene activity within hospitals. However, current data collection methods are significantly flawed and the resulting conclusions drawn from these reports, regarding the efficacy of this method, are tenuous. The method of data collection commonly quantifies the volume of hand gel consumed, with no measure of gel wastage or premature replacement of gel containers before their contents are completely exhausted. Additionally, data does not distinguish between patient, visitor or health care worker consumption within the surveyed location.
Concurrently, this approach to disease transmission prevention has a number of significant additional disadvantages, specifically associated with the human compliance required to ensure its effectiveness. Firstly, this method of transmission prevention and its efficacy are entirely dependent on the individuals due diligence in utilising this method of infection prevention with sufficient frequency. This is further compounded by the necessity to comply both before and after any and all contact with potentially infectious sources, such as patients or hospital/health care service unit equipment. Given the numerous factors that influence this aspect (e.g. patient behaviour/belief system, hospital/health care service unit culture, product availability, location of product dispensers/applicators, hand washing technique etc.), this method of infection transmission prevention is effective when utilised but far from exhaustive. Recent studies have shown that there is still a significant variation in the alcohol-based gel consumption from hospital to hospital nationwide. Worryingly, additional studies looking at consultant compliance reported that consistently low hand washing rates were observed, in spite of special education programmes and subsequently monitored evaluation of consultant technique and hand washing compliance. An ideal solution to the problem would serve to remove the element of user compliance and ensure a mandatory but unobtrusive method of disinfection of the users hand and/or the associated equipment surface.
Secondly, this method of transmission is only one method by which HCAIs are spread throughout hospitals and HCSUs. Indirect contact and common vehicle transmission are rarely implicated in disease transmission, despite the fact that the surrounding environment acts as a reservoir for a multitude of infectious micro-organisms. Inadvertent exposure to such environmental opportunistic pathogens may result in infections with significant morbidity and/or mortality. The environmental reservoir can act as a very efficient way for micro-organisms to spread, with enterococci as an example. This micro-organism can persist on a dry environmental surface in a viable infectious state for up to seven days, with some environments supporting survival for as long as four months after initial contamination.
Thirdly, transmission of micro-organisms from environmental surfaces to patients is largely via hand contact with the surface in question. Although it is well accepted that hand hygiene is a vital component in the HCAI transmission cycle, environmental disinfection is rarely promoted amongst the general population. This is especially worrying given the high levels of patient, visitor and staff mobility and interaction within typical specialist Hospitals and HCSUs worldwide. In fact it can be argued that it is the public population, not the staff that pose the highest risk regarding the introduction of pathogens into the hospital/HCSU setting.
Finally, one of the biggest dangers relating to contamination of environmental surfaces is the efficacy of alcohol-based hand gels. It has been long accepted by the U.S. Food and Drug Administration (FDA) that germicidal chemicals, approved by the FDA as skin antiseptics (such as alcohol-based gels), are completely inappropriate for use as environmental surface disinfectants. This serves to highlight the vital role that regular environmental disinfection plays in the HCAI transmission cycle. Specialist units within Hospitals (such as burns units) are particularly susceptible to HCAIs found on environmental surfaces, given that dermally-compromised patients are missing the bodies most fundamental form of protection against micro-organisms, namely skin.
Contaminated hands have been shown to be extremely effective vectors for disease transmission both from and to inanimate equipment, specifically being capable of supporting micro-organism transfer to additional surfaces. Given the average rate of hand hygiene compliance of approximately 50%, the transiently contaminated hand of an average health care worker (contaminated by an inanimate object) becomes a major route of transmission. This highlights the significant problem with the primary reliance on hand hygiene as the major preventative measure against HCAIs. Hand hygiene alone is not effective if the environment itself is heavily contaminated. The problem with hand washing is that it is impossible to get everyone to do it at the most appropriate and effective time.
High touch surfaces (such as door handles, door knobs etc.) need to be cleaned regularly given the high daily touch rate, and consequently potential for HCAI transmission, of these surfaces within a Health Care setting. There have been a significant number of scientific studies that have been conducted that provide significant evidence of the role the inanimate environment plays in the transmission cycle. This has lead to the widespread acceptance of the importance of environmental cleaning, especially in the control of nosocomial outbreaks. In spite of this widespread acknowledgment, priority is typically given to the cleaning and disinfection of floors and toilet areas. A number of devices have been proposed to provide self cleaning door handles or door knobs.
One device that attempts to solve the problem of cleaning door handles regularly is disclosed in U.S. Pat. No. 4,046,508, issued to McDonald. The McDonald patent discloses a self-cleaning door handle apparatus that is intended to be mechanically operated when the door is opened. As can be seen in the figures and described in the specification, it is intended that a rod is to be pushed by the opening of the door, which causes a pawl to engage a gear to turn a wheel, which functions as the door handle. As the wheel turns, it passes through a wipe that applies a sterile solution to the wheel from a reservoir. The apparatus also has a squeegee to dry the surface of the wheel. A critical flaw in this invention, however, is the fact that the wheel turns as the user operates the door. This is precisely when the device should not operate because the user is grasping the wheel. Moreover, the inherent design of using the push rod will not function as anticipated and makes the device prone to jamming. In particular, the travel distance between the door and the door jamb is insufficient to push the rod a sufficient distance to drive the wheel. Therefore, there is a need of a self-cleaning door handle device that does not operate while the user is grasping he handle and a self-cleaning door handle device that functions properly and is less prone to jamming.
Another U.S. Pat. No. 7,080,427, Campopiano, discloses a self-cleaning handle for a self-closing door. The door is movable by a user between a normally closed position and an open position, and is automatically moved from the open position back to the closed position. The handle having a housing secured to said door and a handle rotatably mounted in the housing. An unexposed portion of the handle is disposed within the housing and an exposed portion of the handle is exposed for grasping by a user to open the door. A cleaning wipe is disposed within the housing and is slidably engaged with the unexposed portion of said handle. This patent asserts that the gap between the body of an open door and its associated door jam is insufficient to drive a door handle self-sterilising device. This patent does not include a method of preventing damage to the device if the door handle is not allowed to operate during door closing and is subsequently driven by repetitive door opening and closing cycles. This is a serious flaw in the design of this patent. This device does not appear to have a safety system, preventing the device from operation if the user holds the handle while the door closes and the device tries to operate. This is a major safety flaw. This patent describes a direct-drive device that would not work on doors that swing both ways, such as those found in hospitals or HCSUs.
There is therefore a need to provide a device system and method to sterilise/disinfect a surface effectively and prevent the transmission of diseases in an environment, for example a hospital, which overcomes the above mentioned problems.